Egg carton with collapsible bubbles

ABSTRACT

A plastic egg carton that enables secure packaging of different size eggs, preferably in both oriented and non-oriented positions, while also allowing for easy filling, closing, handling and packing in shipping containers. The egg carton has a base tray and a lid hingedly connected to the tray for pivoting between open and closed positions. Each cell of the base tray has a plurality of collapsible bubbles formed in the cell sidewall, the bubbles extending radially inwardly in a relaxed state (when no egg or an egg up to a predetermined size (diameter) is present in the cell) and configured to move (compress) outwardly when eggs of increasing size (diameter) above the predetermined size are placed in the cell, thereby accommodating a range of different size variations, and holding each received egg in a vertically aligned position in its cell. The lid post also has a plurality of collapsible bubbles. The bubbles in the cell sidewalls and lid posts collectively hold each egg, within a predefined range of egg sizes, vertically upright in the cell pocket, resisting movement in the horizontal (lateral) direction, and cushioning the egg at its point of maximum girth (maximum width) from compressive forces (lateral impacts).

FIELD OF THE INVENTION

The present invention relates to plastic egg cartons and more particularly to an egg carton that will protect various size eggs in both oriented and non-oriented positions.

BACKGROUND

Egg cartons are subjected to multiple adverse mechanical forces and environmental conditions during filling, handling and transport between loading and distribution centers, store shelves, and the ultimate consumer's home. They typically encounter automated equipment for filling, packaging, loading, unloading, stacking, restacking and transport. During each of these encounters, the goal is to resist egg breakage by stabilizing and holding the eggs in a protected environment, in a carton that can be manufactured in a cost effective manner.

Plastic egg cartons are available with flexible walls between the cell pockets to protect the eggs and prevent them from moving into adjacent cell pockets. However, during handling, such as while loading cases of egg cartons onto a grocery pallet, and then stacking the cases 5 to 6 high on the pallet, the cases/cartons may be thrown onto the pallets and/or bump into each other, causing the eggs to come out of their cell pockets and make contact from a hard side impact blow. Also, when scanning bar codes on lid tops, the eggs can be displaced and make contact. While one carton design may provide structural re-enforcements that accommodate and protect a specific egg size category (e.g., medium, large, extra-large, or jumbo), few cartons can accommodate a range of sizes or even the variation in size that often occurs within a specific egg size category. For example, jumbo eggs can vary between super jumbo (weighing from 2.83 to 3.00 ounces per egg) and regular jumbo (weighing from 2.5 to 2.75 ounces per egg). If even one egg out of a dozen moves in its cell pocket because it is slightly wider or shorter than the typical egg in the size group for which the carton was designed, it creates broken eggs for the retailer to clean up as well as soiled cartons that cannot be sold.

Thus, there is need for an improved egg carton construction that provides better egg protection for eggs of varying dimensions when encountering adverse mechanical forces and environmental changes during filing, packaging, transportation and storage. At the same time, there is a need to manufacture such cartons in a cost effective manner, provide overall carton dimensions that fit within standard case sizes and avoid a redesign of the existing handling equipment.

SUMMARY

The present invention relates to an improved plastic egg carton having one or more structural features that enable secure packaging of different size eggs, preferably in both oriented and non-oriented positions, while also allowing for easy filling, closing, handling and packing in shipping containers. The improved structures hold each egg vertically aligned in an individual cell and minimizes egg movement in the cell. This results in better egg protection, and less breakage. Being able to accommodate various size eggs without requiring a corresponding increase in the footprint (overall size) of the carton provides advantages such as less material costs, use of existing (standard size) containers, and/or more cost efficient transport (e.g., shipping less air).

In one embodiment, an egg carton is provided having a base tray and a lid hingedly connected to the tray for pivoting between open and closed positions. The tray and lid have respective peripheral edges that mate with one another in the closed position, the egg carton having in the closed position a length and a width in a horizontal plane, and a height in a vertical direction transverse to the horizontal plane. The base tray of the carton has a rectilinear matrix of cells, i.e., arranged in transverse rows and columns along the length and width of the carton, each cell having a bottom wall and a sidewall and adapted to hold various sized eggs within a range of different size variations. A vertical cell post is formed at an intersection (i.e., cross-hair (+)) of four adjacent (2×2 matrix of) cells in the base tray, the cell post comprising an extension of the intersecting sidewalls of the four adjacent cells. The lid, hingedly connected to the tray, has a plurality of interior lid posts extending downwardly toward the tray for mating with a respective cell post when the lid is closed over the base. As used herein, “mating” means adapted to respectively contact or be disposed in close proximity to; actual contact between the mating surfaces may occur whenever the lid and base tray are in a closed position, or only when in a closed position and an additional top load (force) is applied to the carton, e.g., when stacking the cartons on top of one another. The mating surfaces of the cell posts and lid posts increase the top compressive strength of the closed carton, and/or its resistance to side load impacts. Still further, the cell posts can help align the eggs as they are deposited (dropped) into the individual cell pockets from above, e.g., by an automatic egg loader. The mating cell and lid posts are preferably provided at the intersection of every four cells (2×2 cell matrix) in the base tray.

In one embodiment, each cell of the base tray has a plurality of collapsible bubbles formed in the cell sidewall, the bubbles extending radially inwardly in a relaxed state (when no egg or an egg up to a predetermined size (diameter) is present in the cell) and configured to move (compress) outwardly when eggs of increasing size (diameter) above the predetermined size are placed in the cell, thereby accommodating a range of different size variations, and holding each received egg in a vertically aligned position in its cell. The lid post also has a plurality of collapsible bubbles, similarly extending radially inwardly in a relaxed state (when no egg or an egg up to a predetermined size (diameter) is present in the respective adjacent cell) and configured to move outwardly when an egg exceeding the predetermined size is placed in the cell. The bubbles in the cell sidewalls and lid posts collectively hold each egg, within a predefined range of egg sizes, vertically upright in the cell, resisting movement in the horizontal (lateral) direction, and cushioning the egg at its point of maximum girth (maximum width) from compressive forces (lateral impacts).

In one embodiment of the invention a plastic egg carton is provided comprising:

a tray and a lid hingedly connected to the tray for pivoting between open and closed positions, the tray and the lid having respective peripheral edges that mate with each other in the closed position, the egg carton having in the closed position a length and a width in a horizontal plane, and a height in a vertical direction transverse to the horizontal plane;

the tray having a cell matrix comprising a plurality of equal size cells for receiving individual eggs, the cells being arranged successively adjacent one another along the length and width of the carton and each cell having a central vertical axis aligned with the height of the carton and extending upwardly toward the lid;

each cell having a bottom wall and a sidewall extending upwardly from the bottom wall to form a corresponding one of the cells, and the tray having a plurality of cell posts, each cell post being formed at an intersection of four adjacent cells as an extension of the sidewalls of the four adjacent cells, and each cell post having a central vertical axis aligned with the height of the carton and extending upwardly toward the lid;

the lid having a plurality of lid posts, each lid post being co-axially aligned with the axis of a respective cell post and extending downwardly toward the tray with a mating surface for engaging with the respective cell post when the lid is in the closed position;

the tray and lid having a plurality of collapsible bubbles, disposed on the cell sidewalls and the lid posts, that are each movable from an innermost relaxed state configured to engage a smaller size egg within a range of different size variations, outwardly to a plurality of compressed states, to engage an ovoid surface area of an egg disposed in the respective cell so as to deter movement and hold in vertical alignment with the central vertical cell axis any size egg within the range of different size variations,

wherein the collapsible bubbles are configured to collapse progressively radially outwardly away from the central vertical cell axis as eggs of increasing size within the range are introduced into the cell.

In one embodiment, each cell sidewall has a contoured interior surface configured to engage an ovoid shape of an egg, and a plurality of the collapsible bubbles are disposed on the contoured interior surface and extend radially inwardly from the contoured interior surface toward the central vertical cell axis in the relaxed state.

In one embodiment, each lid post has a plurality of partial ovoid shaped depressions for engaging the ovoid shape of eggs received in the adjacent cells, and at least one of the collapsible bubbles is disposed on each depression and extends radially inwardly toward the respective central vertical cell axis in the relaxed state.

In one embodiment, each lid post has four of the partial ovoid depressions, one for engaging with eggs received within each of the four adjacent cells when the lid is in the closed position.

In one embodiment, each cell post has an uppermost surface for engaging with a mating surface of the respective lid post when the lid is in the closed position.

In one embodiment, the lid includes a connecting wall between each pair of adjacent lid posts.

In one embodiment, the collapsible bubbles have a wall thickness that is less than a wall thickness of the cell sidewalls.

In one embodiment, the collapsible bubbles have a wall thickness of at least 35% less that the wall thickness of the cell sidewalls, more preferably in a range of 40 to 60% less, and still more preferably in a range of 45 to 50% less.

In one embodiment, the cell sidewalls have a wall thickness in a range of 35 to 75 mils, and the collapsible bubbles have a wall thickness in a range of 20 to 45 mils.

In one embodiment, the range of different size variations is from 50 t 78 ounces per egg, with the egg disposed in either an oriented or a non-oriented direction in the cell.

In one embodiment, the range of different size variations is from 65 to 78 ounces per egg, with the egg disposed in either an oriented or a non-oriented direction in the cell.

In one embodiment, the range of different size variations is from 50 to 65 ounces per egg, with the egg disposed in either an oriented or a non-oriented direction in the cell.

In one embodiment, the plastic is a foam or non-foam plastic material.

In one embodiment, the plastic is a foam plastic material.

In one embodiment, the plastic is styrene foam material.

In one embodiment, the plastic is one or more of polyester, polyethylene, polylatic acid, and polystyrene, including polymers, copolymers, mixtures and blends thereof.

In one embodiment, the carton comprises a non-foam polyester.

In one embodiment, the carton comprises an integral foamed sheet of polystyrene material.

In one embodiment, the cell sidewalls have a thickness in a range of 35 to 75 mils.

In one embodiment, the base tray has a 2×6 matrix of the cells.

In one embodiment, the base tray has a 2×3, 2×4, 2×5, 2×6, 3×3, 3×4, 3×5, 3×6, 4×4, 4×5, 4×6, 5×5, 5×6 or 6×6 matrix of the cells.

In one embodiment, each cell has an arcuate, outwardly bowed sidewall portion sized to receive a major cell diameter of a jumbo egg in a range of about 1.75 to about 2.06 inches, and the distance between the cell bottom wall and the lid is configured to hold a jumbo egg in a height range of 2.461 to 2.750 inches.

In one embodiment, the sidewalls of two adjacent cells form a cell divider which prevents contact between eggs in the adjacent cells.

In one embodiment, the carton in the closed position has a length of from about 11.62 to about 12.00 inches, a width of from about 3.95 to about 4.00 inches and a height of from about 2.62 to about 3.125 inches.

In one embodiment, the cell bottom walls are movable to accommodate eggs of various sizes in the range.

In one embodiment, the movable cell bottom walls and collapsible bubbles accommodate eggs that are disposed in either an oriented or a non-oriented direction in the cells.

In one embodiment, the carton is filled with eggs of varying sizes in the range.

In one embodiment, a plurality of filled egg cartons is arranged in a vertical stack.

In one embodiment, a container holds the vertical stack of filled egg cartons.

In one embodiment, a container holds a full case or half case of the filled egg cartons.

In one embodiment, a method is provided for assembling a stack of the egg cartons, including for each of a plurality of the cartons, filling the cells of the egg carton with eggs of varying sizes in the range, closing the lid over the base, and stacking a plurality of the filled egg cartons in a vertical stack.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings depict one or more embodiments of the invention wherein:

FIG. 1 is a top perspective exterior view of an egg carton having a base tray and a hinged lid in a closed position according to one embodiment of the invention;

FIG. 2 is a top perspective interior view of the egg carton of FIG. 1, showing the base tray and hinged lid in the open position, the base tray having a rectilinear 2×6 matrix of egg-receiving cells and a central longitudinal row of five cell posts, and the lid having a central longitudinal row of five lid posts that are each vertically aligned with and mate with a respective cell post in the closed carton position, and with collapsible bubbles provided on both the cell sidewalls of the base tray and the lid posts;

FIG. 3 is a bottom perspective exterior view of the egg carton of FIG. 2 in the open position;

FIG. 4A is a front plan view of the egg carton of FIG. 2 in the open position;

FIG. 4B is a rear plan view of the egg carton of FIG. 2 in the open position;

FIG. 4C is an end plan view of the egg carton of FIG. 2 in the open position;

FIG. 4D is a end plan view of the egg carton of FIG. 4C in the closed position;

FIG. 5 is a top perspective interior view of the egg carton of FIG. 2, in the open position but now partially filled with three eggs of different sizes and orientations in the three left-hand cells of the front row, the three remaining cells of the front row and the six cells of the rear row all being empty;

FIG. 6 is a top perspective, partial sectional view of the FIG. 5 partially filled egg carton in the closed position, with the lid and the top ends of the three eggs partially cut-away, showing the collapsible bubbles on the lid posts engaging the eggs and holding them vertically upright in the cells;

FIG. 7 is a longitudinal sectional view of the partially filled FIG. 5 egg carton in the closed position, showing the contours of the lid posts and cell sidewalls and the collapsible bubbles engaging each egg and holding it vertically upright in its respective cell;

FIG. 8 is a top plan view of an unfilled egg carton of FIG. 1 in the closed position, showing the central trough and the lid post structures;

FIG. 9 is an sectional view of the closed egg carton taken along section line 9-9 of FIG. 8, showing one egg in phantom lines to illustrate how the various contoured cell and lid structures and bubbles engage and hold the egg vertically aligned in the cell;

FIG. 10 is a side view of a plurality of filled egg cartons stacked on a pallet, showing a crane depositing another group of stacked cartons on top of the existing stack on the pallet; and

FIGS. 11A-D are perspective views of different stacking patterns of cartons in different types of containers, FIG. 11A showing a full case of filled egg cartons stacked in parallel vertical columns in a cardboard box, FIG. 11B showing a full case of filled egg cartons cross stacked in a cardboard box with each row in an alternating cross pattern, FIG. 11C showing a half case of filled egg cartons stacked in parallel vertical columns in a wire basket, and FIG. 11D showing a half case of filled egg cartons cross stacked in a wire basket with each row in an alternating cross pattern.

DETAILED DESCRIPTION Overview

FIGS. 1-9 illustrate one embodiment of a plastic egg carton 10 according to the present invention. The carton includes a base tray 30 and lid 20, with a 2×6 matrix of egg-receiving cells 40 in the base tray 30, mating cell posts 60 and lid posts 25, and a plurality of collapsible bubbles 15 disposed on the cell sidewalls 45 and lid posts 25 that deter movement of and hold in vertical alignment with a central vertical cell axis A any size egg 4 within a range of difference size variations. With the lid closed over the base tray, the carton has a 2×6 matrix of cell pockets formed by vertically aligned structures of the lid and base tray, namely the base cells, cell posts and lid posts, and contoured surfaces of the cell sidewalls and lid posts. The cell pockets are formed of uniform size, but are provided with collapsible bubbles 15 that progressively move radially outwardly in response to eggs of increasing size (e.g., diameter) to allow the cells to securely hold different egg sizes in a range of sizes, e.g., jumbo eggs, between 65 and 75 grams each, in either an oriented (small end down) or non-oriented (small end up) position in the cell.

In the present embodiment, the carton occupies no more than a standard (non-jumbo) egg carton footprint. The invention is not limited however to such standard footprint egg cartons, or to jumbo eggs; rather, the mating lid and cell post and collapsible bubble structures can be used with substantially any cell and carton size, for holding different ranges of egg sizes, where the overall carton dimensions are not limited. Furthermore, the increased strength and security of the mating lid and cell post structures and bubbles are useful for various purposes in addition to improved egg protection, including light weighting of the carton (saving material costs), the use of alternative materials and/or manufacturing processes, increasing the stacking height, etc.

FIGS. 1-4D show an unfilled egg carton 10 in both open and closed positions. FIGS. 5-9 show the same carton 10, with eggs of different sizes placed in select cells, to illustrate the operation of the collapsible bubble structures in holding each of the different size eggs, within a specified size range, upright in a vertical position in its respective cell and resistant to movement in the cell. FIGS. 10-11D illustrate various methods and containers for handling, stacking, packing and shipping a plurality of filled egg cartons, while the collapsible bubble structure holds each egg (of different sizes) securely in its cell and resistant to movement or breakage of the eggs while subjected to top loads (stacking) and lateral (side-to-side) impact forces during handling.

FIG. 1 is a top perspective exterior view of the closed 2×6 matrix egg carton 10. The carton is comprised of a lid 20 connected via a hinge 12 to a base tray 30, the closed base tray and lid providing a plurality of egg receiving cell pockets arranged in a rectilinear 2×6 matrix. When closed the carton 10 occupies a volume having a length L, width W, and height H (see FIGS. 4D and 7-8).

FIGS. 2-3 are top and bottom perspective views of the same carton 10 in an open position, showing the carton interior (top) surface 11 (in FIG. 2) or the carton exterior (bottom) surface 13 (in FIG. 3). The 2×6 base cell matrix includes four corner cells 42, one at each corner of the base tray, and eight edge cells 41, with four edge cells extending along each of the two opposing front FLE and rear RLE longitudinal edges of the base tray, between the corner cells. At each cross-hair (+) intersection of four adjacent cells (2×2 matrix) a cell post 60 is provided. Each cell sidewall 45 is configured to have a contour (shape and dimensions) complementary to the shape of an egg 4 (shown in solid lines in FIGS. 5-7 and in dashed lines in FIG. 9). As used herein, “complementary” means conforming at least in part to the ovoid contour (size and shape) of the egg being held or the surface being mated therewith. It is contemplated that various sized eggs can be inserted into a cell, in one or both of an oriented and non-oriented direction.

In the present embodiment, the carton 10 is integrally molded from a sheet of thermoplastic material, here polystyrene foam, which sheet is formed into an end product (carton) having the structural components described herein. The carton can be made via conventional molding processes, e.g., pressing the polystyrene foam sheet between male and female dies to form shaped lid and base portions and then removing (trimming) any remaining portions of the sheet to form an integral carton. The formation and structure of components such as the hinge 12, closing flap 92 with locking nubs 93, and associated locking apertures 94 (which receive the locking nubs on the flap to securely close the lid to the base tray), are shown and described in the prior art such as in U.S. Pat. No. 6,012,583 and U.S. Pat. No. 5,494,164, the entire disclosures of which are incorporated herein by reference as if fully set forth herein.

Base Tray

As shown in FIGS. 1-5, the base tray portion 30 of the carton 10 comprises a rectilinear matrix of egg-receiving cells 40, aligned along rows and columns of the cell matrix, each cell being formed to receive and accommodate a single egg. Each cell 40 has a sidewall 45 having an inner receiving surface contoured to receive the ovoid shape of an egg. The sidewall 45 extends upwardly from a bottom cell wall 47 (see FIGS. 3 and 7) to define an open top end of the cell. Two adjoining sidewalls 45, 45, between adjacent pairs of cells 40, cooperatively define a cell junction 43. The cell junction 43 preferably includes a rounded upper shoulder portion at the top end of the joined sidewalls. The sidewalls 45 and cell junctions 43 are generally flexible to respond to pressure applied during packaging, transportation and/or storage of the eggs.

As shown in FIGS. 3, 7 and 9, each cell 40 has a bottom wall 47 with an outermost annular standing ring 147 forming the lowermost planar surface on which the base tray rests in the common plane BP. This allows the planar bottom of one carton to be mechanically stacked or deposited on top of the uppermost planar lid surface 21 of another carton (see FIGS. 10-11). By force of gravity, the bottom wall ring surfaces 147 bear against the top surface 21 to provide a degree of stability against lateral LAT or longitudinal LONG movement due to friction between the top surface 21 and bottom ring surfaces 147.

The bottom wall of each cell further includes, radially inwardly of the annular ring 147, a raised central portion 148 having an outwardly curved (concave) interior surface (in the relaxed state) configured to engage one end of the egg. FIG. 7 shows, for example, the small end of eggs 4A and AB pointing down and engaging the central bottom portion 148 in the two left-hand cells 45A and 45B respectively, and another egg 4C oppositely disposed with its large end pointing down and engaging the central bottom portion 148 of cell 45C. The cell bottom wall is movable, i.e., the bottom central portion 148 can move up and down (vertically) with respect to the annular outer ring 147, to accommodate eggs of different heights, and different orientations, in the cell.

The cell sidewall 45 has an interior surface that is outwardly curved (concave) extending upwardly from the bottom wall 47 and gradually increasing in circumferential area moving upwardly toward a top end of the cell wall that forms a cell junction 43 with an adjacent cell. The cell sidewalls 45 and junctions 43 are made relatively thin, compared to the thickness of the cell posts 60 and lid posts 25, so that the cell sidewalls 45 and junctions 43 can readily move to accommodate larger size eggs and/or absorb side (lateral) forces. The movable cell bottom wall 47 helps accommodate eggs of different heights and absorb vertical (e.g., top loading) forces. Together, the sculpted sidewall surfaces and bubbles, together with the movable bottom wall, provide improved egg protection by securing the eggs within an individual cell pocket compartment. Preferably, the cell contour is designed to handle both oriented and non-oriented eggs.

At each intersection of four adjacent (2×2 matrix of) cells within the tray 30, a vertically aligned cell post 60 is formed as an extension of the merged sidewalls 45 of the four adjacent cells 40. The cell post 60 has a central dome 61 with an uppermost surface 60U for engaging with a lowermost surface of a vertically aligned lid post 25, as shown in FIG. 7. The uppermost surface 60U of the cell post 60, and lowermost surface 25L of the lid post 25, lie in or closely adjacent to a horizontal plane HP defined by upper peripheral edge 31 of the base tray, the peripheral edge 31 providing a mating surface for the lower peripheral edge 27 of the lid 20.

Each cell post 60 has a central vertical cell post axis CPA that extends axially down the center of the cell post 60, parallel to the height H of the carton, and parallel to the central vertical axis of the cell A (see FIG. 7). The cell post 60 is preferably generally tubular in shape and typically hollow. Both CPA and A are aligned with the height H direction of the closed carton and are disposed transversely (about 90 degrees) to the bottom walls 147 of the cells that lie in the base plane BP.

The cross-hair construction of the cell posts 60 provide increased compression strength and help maintain the cell posts and lid posts in alignment. The individual cell sidewalls 45 and sidewall junctions 43 preferably are of a lesser thickness than the cell posts 60 so the sidewalls and sidewall junctions can yield and flex to protectively hold the various sized eggs against breakage, particularly when exposed to lateral forces. The cell sidewall extensions that connect to the cell post dome 61 provide resistance at least in the axial (height) direction CPA against downward compressive forces that may be exerted in the downward direction by a lid post 25 bearing down against a cell post 60 when one carton is stacked on top of another. They also resist side impact forces and help maintain the lid and cell posts in axial alignment (i.e., the central axes of both the lid post and cell post are aligned along CPA).

Lid

As shown in FIGS. 1-4D, the lid 20 comprises a generally flat (planar) uppermost top wall 21 and a surrounding downwardly-extending peripheral sidewall 23. The lid sidewall includes opposing front 23F and rear 23R walls, opposing left end 23LE and right end 23RE walls, and four corners 29 connecting the same. The rear wall 23R connects to the base tray at hinge 12, while the remaining three walls 23F, 23RE and 23LE have a lowermost peripheral edge 27 that mates with a peripheral upper edge 31 of the base tray 30 (in horizontal plane HP).

The lid top wall 21 has a central recessed trough 50, forming a central longitudinal divider wall (aligned with the LCL), with five (5) downwardly projecting lid posts 25 each arranged to mate, in the closed position, with one each of the five (5) cell posts 60 of the tray 30. As best shown in FIG. 7, each lid post 25 comprises a hollow tubular member, similar to the cell post 60. Each lid post 25 has a central vertical axis that is co-axial with a respective cell post axis CPA as described above, and parallel to the height direction H of the closed carton. The lid posts are uniformly spaced apart along the longitudinal centerline LCL of the closed lid and carton. At the center of each lid post is a lowermost flat mating surface 25L adapted to engage the uppermost surface 60U of the dome 61 of the cell post when the lid 20 and tray 30 are in a closed position.

The trough 50 (see FIGS. 1, 3 and 5) is formed as a generally elongated rectangular depression within the body of the planar top wall 21 and peripheral sidewall 23, the trough having opposing longitudinal front and rear facing side walls 52 and opposing lateral end walls 51 that extend downwardly and below the planar top wall 21 of the lid 20. As shown in FIG. 8, the trough 50 includes connecting wall portions 54 between each pair of adjacent lid posts 25, while the two end lid posts are connected to opposing lateral walls 51 of the trough respectively.

The trough 50 further includes contoured (partial ovoid shaped) portions 28 that form a part of the cell pocket structure for engaging and securing/protecting the eggs in the cell pockets. Each lid post has four (4) contoured surfaces 28 arranged in a cross-hair (+) configuration for mating (one each) with four eggs in the respective four adjacent cells (2×2 matrix) of the base tray, for each associated (vertically axially aligned) lid post and cell post pair. Two of the four ovoid-shaped contoured portions 28 of each lid post are disposed on the front side of the longitudinal centerline LCL (28F as shown in FIG. 8), and the other two on the rear side of LCL (28R in FIG. 8), so as to mate with eggs in the base cells on opposing sides of the longitudinal centerline LCL. The contoured surfaces of the lid posts mate with the outside surface of an egg 4 to protect the egg against lateral LAT or longitudinal LONG movement within a cell when the lid 20 is closed down onto the tray 30.

Cross Sectional Views Showing Operation of Collapsible Bubbles

FIGS. 5-9 illustrate the operation of the collapsible bubble structures on the base tray and lid. Representative eggs 4A-4C, of various sizes and orientations are included to illustrate how the collapsible bubble structures progressively move (collapse) to accommodate eggs of increasing size, as well as different orientations, in the cell pockets.

FIG. 5 shows the collapsible bubbles 15 in the base tray and lid. Each cell 40 of the base tray has four bubbles 15B, uniformly spaced around the cell sidewall 45 circumference, i.e., 90 degrees apart. The four base cell bubbles 15B are provided, one each, on opposing front-most 45FA and rear-most 45RA areas of the cell sidewall, and on opposing right-end 45RE and left-end 45LE areas of the cell sidewall (see FIGS. 4A and 4D). Alternatively, there may be a higher or lower number of base cell bubbles on each cell sidewall and the bubbles may be disposed at different positions around the circumference, and need not be uniformly distributed. In a preferred embodiment, there are at least four bubbles, and they are uniformly distributed around the circumference. In one alternative embodiment there may be four additional bubbles in each base cell, uniformly distributed (one each) at the four mid points equidistant between where the four bubbles of the current embodiment are positioned.

Two lid post bubbles 15L, in each cell pocket of the present embodiment, are axially aligned at respective mid-points equidistant between two adjacent base cell bubbles 15B. This provides six (6) movable (collapsible) bubbles associated with the egg in each front and rear edge cell pockets 41 (four in the base cell itself and one each in the two adjacent lid posts). However, the four end cell pockets 42 each have only five (5) movable (collapsible) bubbles in contact with the egg in the cell pocket (four in the base cell and one in the adjacent lid post). In an alternative embodiment, there may be additional collapsible bubbles provided in the lid, such as in the lid sidewall 23 or lid corners 29, configured to engage an egg in the adjacent cell pocket. The collapsible bubbles of the lid and base are disposed vertically both above and below the maximum egg diameter MED in the cell pocket (as described below with respect to FIG. 7).

FIG. 6 is a partial sectional view of the carton of FIG. 5, now in the closed position, with the uppermost portion of the lid and tops of the eggs sectioned (cut away) to show how the collapsible bubbles (of the lid 15L and base 15B) can hold both oriented and non-oriented eggs upright (vertically) in the same size cell pockets of the closed carton. The central most egg 4C is disposed in a non-oriented position, with the small end of the egg pointing up; the immediately adjacent egg to the left 4B, is disposed in the oriented position, with the small end pointing down; the leftmost egg 4A, adjacent to 4B, is similarly positioned small end down. FIG. 6 shows: a) two lid bubbles 15LC on one lid post 25C engaging (holding vertically to deter longitudinal or lateral movement in the cell pocket) the small end of the non-oriented egg 4C; and b) two lid bubbles 15LB on the next adjacent lid post 25B, engaging (holding) the larger end of the oriented egg 4B. Lid bubbles 15LC, engaging the small end, are less compressed that lid bubbles 15LB, engaging the large end.

FIG. 7 a longitudinal sectional view of the lid and tray in a closed position, showing the three eggs 4A, 4B, and 4C in the three left hand cell pockets. The exterior bottommost surfaces 147 of the cells lie in the base plane BP. The complementary mating surfaces of the cell and lid posts 160, 125 are in engagement or are in close proximity thereto, at or closely adjacent to a mid-height longitudinal horizontal plane (HP), that lies equal-distant between the BP and top plane TP.

The two left-most eggs 4A and 4B are disposed small end pointed down (oriented), while the centermost egg 4C is oppositely disposed small end pointed up (non-oriented). The directional orientation and dimensions of the egg are defined by an egg height (EH) that is vertically aligned with the cell axis A, and a transverse maximum egg diameter (MED) aligned horizontally with the HP and LCL. The cell dividers 43 between each adjacent egg sidewall are flexible and fold inwardly if a larger size egg is disposed in the adjacent cell(s). The collapsible bubbles 15 in the base cell and lid progressively collapse (move outwardly) as eggs of increasingly larger size (diameter) are disposed in the cell. The collapsible bubbles 15 also move to accommodate the different orientations of the egg; as shown, the left most eggs 4A and 4B are pointed small end down and thus the bubbles are less compressed due to the smaller egg diameter engaged by the bubbles, while the center egg 4C to the left, oriented small end up, presents a larger diameter in that base cell which is accommodated by greater movement (collapse) of the bubbles in that cell.

FIG. 8 is a top plan view showing the five (5) lid posts 25 formed in and uniformly spaced apart along the central longitudinal trough 50 of the lid (lying on the LCL). The four bubbles 15L on each lid post 25 are symmetrically disposed on either side of the LCL, two bubbles 15LF disposed on the front side of the LCL and the other two bubbles 15LR disposed on the rear side of the LCL.

FIG. 9 is a lateral sectional view taken along the line 9-9 of FIG. 8. One egg 4C is shown in dashed lines, resting in the cell 40 of the carton 10, vertically disposed small end pointed up (non-oriented). Here the larger lower end of the egg is shown engaging the cell sidewall 45, between the cell bubbles. A collapsible lid bubble 15L is now engaging the upper end (small end) of the egg 4C; in this example, the lid bubble is not collapsed while it engages the smaller upper end of the egg. If an egg with a wider upper end diameter were introduced in the cell pocket, the same lid bubble would progressively collapse to accommodate the larger width, and still engage the egg. The base cell bubbles 15B in this embodiment are rotated (disposed) approximately 45 degrees (around the cell circumference) from the lid bubbles to provide more contact points on the egg, while allowing eggs of various sizes and orientations to be held vertical in the cell pocket.

In the embodiment described herein, the closed carton holds 12 jumbo eggs in a 2×6 matrix of cells and has an overall length L of between about 11.62 and about 11.75 inches, a width W of between about 3.95 and about 4.00 inches, and a height H of between about 2.62 and about 2.75 inches. This is the standard volume footprint of a 2×6 carton for non-jumbo eggs. Here, due to the increased strength and security provided by the bubbles and the mating cell and lid post structure, the standard footprint is maintained while accommodating jumbo eggs.

In an alternative embodiment, the carton holds 18 jumbo eggs in a 3×6 matrix of cells, the overall carton having a length of between about 11.62 and about 11.75 inches, a width of between about 5.95 and about 6.00 inches, and a height of between about 2.62 and about 2.75 inches. This is the standard volume footprint of a 3×6 carton for non-jumbo eggs. Again, due to the increased strength and security provided by the bubbles and the mating cell and lid post structure, the standard footprint is maintained while accommodating jumbo eggs.

FIG. 10 shows one embodiment of a method and system for stacking a plurality of filled egg cartons 10. In this example the cartons are stacked on the top planar surface 210 of a pallet 200, typically by a forklift or crane 300. Here, the stacked cartons are shown not enclosed within outer containers. Alternatively, the cartons may be stacked within outer containers such as those shown in FIG. 11, and the containers stacked on top of one another. As shown in FIG. 10, the cartons 10 are stacked vertically in series in direct top to bottom contact, one on top of another, to form a stack 400. Slip sheets 250 are disposed between each sub stack of 4 cartons in vertical depth. The slip sheets 250 may comprise a flexible sheet of paper, plastic or cloth that can be deposited on and extended across the top surfaces of a horizontal layer of multiple side-by-side (horizontally arranged) cartons.

In other embodiments, the egg cartons are held (e.g., enclosed) in outer containers in various stacking patterns. FIG. 11A shows a full case rectilinear paperboard container 230 holding a 6×5 array of 30 2×6 egg cartons 10 stacked in parallel arrangement. The case 230 of FIG. 11A has inner dimensions of about: 23-⅞ inches×11-⅞ inches×13-¾ inches. FIG. 11B shows the same full case container 230 holding 30 2×6 egg cartons 10 stacked in a cross stacking arrangement, wherein successive vertical layers are disposed transverse to the adjacent layer. Alternatively, a half case rectilinear container is provided to hold 15 2×6 egg cartons, in a 3×5 carton matrix. In one embodiment the 15-dozen half case container has inner dimensions of about: 11-⅞ inches×11-⅞ inches×13-⅝ inches. In another embodiment, the 15-dozen half case container has inner dimensions of about: 12 inches×11-⅞ inches×13-½ inches.

In accordance with the previously described embodiment of the invention, wherein a 2×6 egg carton is provided having a standard footprint but which accommodates jumbo size eggs, the above-described standard full case and half case containers can be used for jumbo size eggs, without increasing the dimensions of the full case or half case containers. Similarly, the 3×6 egg carton previously described can be accommodated in standard full and half case containers.

In alternative embodiments, the egg cartons 10 can be stacked in wire baskets 232. FIG. 11C shows parallel stacking of 15 2×6 matrix cartons in a wire basket 232. FIG. 11D shows cross stacking of 15 2×6 matrix cartons in the same wire basket.

In various embodiments, the plastic material of the egg carton is preferably one or more of polystyrene (e.g., polystyrene foam), polyester (e.g., polyethylene terephthalate (PET)), polyolefin (e.g., polyethylene (PE), polypropylene (PP)), or poly(lactic acid (PLA), including homopolymers, copolymers, mixtures and blends thereof, and including virgin and reclaimed (recycled) materials.

While specific embodiments of the present invention have been shown and described, it will be apparent that many modifications can be made thereto without departing from the scope of the invention. Accordingly, the invention is not limited by the foregoing description. 

1. A plastic egg carton comprising: a tray and a lid hingedly connected to the tray for pivoting between open and closed positions, the tray and the lid having respective peripheral edges that mate with each other in the closed position, the egg carton having in the closed position a length and a width in a horizontal plane, and a height in a vertical direction transverse to the horizontal plane; the tray having a cell matrix comprising a plurality of equal size cells for receiving individual eggs, the cells being arranged successively adjacent one another along the length and width of the carton and each cell having a central vertical axis aligned with the height of the carton and extending upwardly toward the lid; each cell having a bottom wall and a sidewall extending upwardly from the bottom wall to form a corresponding one of the cells, and the tray having a plurality of cell posts, each cell post being formed at an intersection of four adjacent cells as an extension of the sidewalls of the four adjacent cells, and each cell post having a central vertical axis aligned with the height of the carton and extending upwardly toward the lid; the lid having a plurality of lid posts, each lid post being co-axially aligned with the axis of a respective cell post and extending downwardly toward the tray with a mating surface for engaging with the respective cell post when the lid is in the closed position; the tray and lid having a plurality of collapsible bubbles, disposed on the cell sidewalls and the lid posts, that are each movable from an innermost relaxed state configured to engage a smaller size egg within a range of different size variations, outwardly to a plurality of compressed states, to engage an ovoid surface area of an egg disposed in the respective cell so as to deter movement and hold in vertical alignment with the central vertical cell axis any size egg within the range of different size variations, wherein the collapsible bubbles are configured to collapse progressively radially outwardly away from the central vertical cell axis as eggs of increasing size within the range are introduced into the cell.
 2. The egg carton of claim 1 wherein each cell sidewall has a contoured interior surface configured to engage an ovoid shape of an egg, and a plurality of the collapsible bubbles are disposed on the contoured interior surface and extend radially inwardly from the contoured interior surface toward the central vertical cell axis in the relaxed state.
 3. The egg carton of claim 2 wherein each lid post has a plurality of partial ovoid shaped depressions for engaging the ovoid shape of eggs received in the adjacent cells, and at least one of the collapsible bubbles is disposed on each depression and extends radially inwardly toward the respective central vertical cell axis in the relaxed state.
 4. The egg carton of claim 3 wherein each lid post has four of the partial ovoid depressions, one for engaging with eggs received within each of the four adjacent cells when the lid is in the closed position.
 5. The egg carton of claim 1 wherein each cell post has an uppermost surface for engaging with a mating surface of the respective lid post when the lid is in the closed position.
 6. The egg carton of claim 1 wherein the lid includes a connecting wall between each pair of adjacent lid posts.
 7. The egg carton of claim 1, wherein the collapsible bubbles have a wall thickness that is less than a wall thickness of the cell sidewalls.
 8. The egg carton of claim 7 wherein the collapsible bubbles have a wall thickness of at least 35% less that the wall thickness of the cell sidewalls, more preferably in a range of 40 to 60% less, and still more preferably in a range of 45 to 50% less.
 9. The egg carton of claim 1 wherein the cell sidewalls have a wall thickness in a range of 35 to 75 mils, and the collapsible bubbles have a wall thickness in a range of 20 to 45 mils.
 10. The egg carton of claim 1 wherein the range of different size variations is from 50 to 78 ounces per egg, with the egg disposed in either an oriented or a non-oriented direction in the cell.
 11. The egg carton of claim 1 wherein the range of different size variations is from 65 to 78 ounces per egg, with the egg disposed in either an oriented or a non-oriented direction in the cell.
 12. The egg carton of claim 1 wherein the range of different size variations is from 50 to 65 ounces per egg, with the egg disposed in either an oriented or a non-oriented direction in the cell.
 13. The egg carton of claim 1 wherein the plastic is a foam or non-foam plastic material.
 14. The egg carton of claim 1 wherein the plastic is a foam plastic material.
 15. The egg carton of claim 1 wherein the plastic is styrene foam material.
 16. The egg carton of claim 1, wherein the plastic is one or more of polyester, polyethylene, polylatic acid, and polystyrene, including polymers, copolymers, mixtures and blends thereof.
 17. The egg carton of claim 1, wherein the carton comprises a non-foam polyester.
 18. The egg carton of claim 1, wherein the carton comprises an integral foamed sheet of polystyrene material.
 19. The egg carton of claim 18, wherein the cell sidewalls have a thickness in a range of 35 to 75 mils.
 20. The egg carton of claim 1, wherein the tray has a 2×6 matrix of the cells.
 21. The egg carton of claim 1, wherein the tray has a 2×3, 2×4, 2×5, 2×6, 3×3, 3×4, 3×5, 3×6, 4×4, 4×5, 4×6, 5×5, 5×6 or 6×6 matrix of the cells.
 22. The egg carton of claim 1, wherein each cell has an arcuate, outwardly bowed sidewall portion sized to receive a major cell diameter of a jumbo egg in a range of about 1.75 to about 2.06 inches, and the distance between the cell bottom wall and the lid is configured to hold a jumbo egg in a height range of 2.461 to 2.750 inches.
 23. The egg carton of claim 1, wherein the sidewalls of two adjacent cells form a cell divider which prevents contact between eggs in the adjacent cells.
 24. The egg carton of claim 1, wherein the carton in the closed position has a length of from about 11.62 to about 12.00 inches, a width of from about 3.95 to about 4.00 inches and a height of from about 2.62 to about 3.125 inches.
 25. The egg carton of claim 1, wherein the cell bottom walls are movable to accommodate eggs of various sizes in the range.
 26. The egg carton of claim 25, wherein the movable cell bottom walls and collapsible bubbles accommodate eggs that are disposed in either an oriented or a non-oriented direction in the cells.
 27. The egg carton of claim 1, wherein the carton is filled with eggs of varying sizes in the range.
 28. A stack comprising a plurality of filled egg cartons of claim 27 arranged in a vertical stack.
 29. A container holding the vertical stack of filled egg cartons of claim
 28. 30. A container holding a full case or half case of the filled egg cartons of claim
 27. 31. A method of assembling a stack of the egg cartons of claim 1, including for each of a plurality of the egg cartons of claim 1, filling the cells of the egg carton with eggs of varying sizes in the range, closing the lid over the base, and stacking a plurality of the filled egg cartons in a vertical stack. 